(1) Field of the Invention
This invention relates to a novel improved process and apparatus for concentrating a component of a gaseous mixture by the utilization of Knudsen diffusion.
(2) Description of the Prior Art
When a gas diffuses through a pore under Knudsen's conditions, its diffusion rate is inversely proportional to the square root of its molecular weight. Accordingly, a gaseous mixture may be subjected to Knudsen diffusion in order to concentrate its lighter component having a higher diffusion rate. This is a well-known fact and, in the prior art, a process has been available in which the lighter component of a gaseous mixture is concentrated and/or separated by feeding the gaseous mixture in a steady state to one surface of a porous membrane. However, the conventional steady-state diffusion process gives only a low enrichment factor for a single stage and hence requires a very large number of stages, which often makes this process impracticable for industrial purposes.